Boris Johnson will say in a speech Monday said the 2015 pact was a success of diplomatic imagination and hard graft that could provide the blueprint to solve the North Korean crisis.

His comments follow Mr Trump’s announcement that he would not certify the Iranian nuclear deal as he’s required to do every 90 days and his repeated threats to pull out of the deal completely.

During campaigning for last year’s presidential election, Mr Trump described the Joint Comprehensive Plan of Action (JCPOA) the “worst deal ever negotiated” and claimed that his predecessor Barack Obama had been hoodwinked by the Iranians.

Mr Johnson will, however, say that the Iran deal – which lifted sanctions in return for suspending Tehran’s drive to secure atomic weapons - represented one of the most valuable agreements signed as part of international non-proliferation efforts.

Mr Johnson will also went out of his way to praise his US counterpart Rex Tillerson for opening the door to dialogue with North Korean leader Kim Jong-un. Mr Trump has previously described Mr Tillerson’s efforts to do business with the regime as a waste of time.

“This is the moment for North Korea's regime to change course - and if they do the world can show that it is once again capable of the diplomatic imagination that produced the nuclear non-proliferation treaty - arduously negotiated - and that after 12 years of continuous effort produced the JCPOA nuclear deal with Iran,” Mr Johnson will say in his speech at the Chatham House thinktank.

But Mr Johnson will stress that the president is also right to “prepare any option” to keep America and its allies safe in the face of North Korea's race to a long-distance nuclear missile.

Mr Johnson will praise the 1970 nuclear non-proliferation treaty (NPT) and the role of the United States in providing a nuclear umbrella for its allies.

“That far-sightedness is now needed more than ever, not only to keep the NPT, but also one of its most valuable complementary accords, the nuclear deal with Iran.”